State of the Art
One of the major problems encountered in the injection of grouting material, such as cement slurry, into grout holes for sealing foundation areas for earthen-filled dams and the like is that of preventing the back-flow of the grouting material from the grouting area up the grout hole past the grouting packer or tube. Many attempts have been made as evidenced in the prior art to provide adequate means for sealing off the grout packer with the surrounding grout hole walls. None of the prior art disclosures have proved to be efficient or effective in providing the sealing means desired.
A second major problem which is encountered in the grouting field is that of removing the grout packer from the grout hole after the grouting has been completed. Typically, the rotating removal of the grout packer tool is hindered by the rough walls of the grout hole. The grout hole typically has sharp projections and edges which extend from the walls into the hole. Very often during removal of the grouting tube, the grout packer becomes lodged against one or more such projections. In addition, during grouting, the grout packer can become surrounded by cement and become grouted in place.
In the past there has been no alternative to disengaging the grout packer from the tubing above, and leaving the grout packer in the grout hole while withdrawing the remaining tubing from the hole. Unfortunately, when it becomes necessary to re-drill the grout hole beyond the grouting area to a lower level, the drill bit encounters the grout packer lodged in the hole and is able to drill through the steel components of the packer only with great difficulty.